Since the inception of modern chromatography, silica based stationary phases have dominated the world of chemical separations. Unfortunately, silica has certain limitations. Under acidic conditions, silica tends to lose its functionality and under basic conditions it dissolves entirely after a matter of hours. Not until recently have alternatives to silica been available such as polymer based stationary phases. These tend to swell when exposed to organic solvents and are therefore not ideal for reversed-phase separations.
Chemists have worked around the limitations of available stationary phases, but these workarounds often result in less than ideal outcomes. For instance, certain separations may need to occur under basic or acidic conditions because the analyte of interest may only be stable under a certain pH range. It is would therefore be ideal to find a phase that could perform a separation under extreme pHs that current phases cannot successfully do separations at.
Diamond has usually been assumed to be inert and relatively little has been done to investigate the possibility of diamond as the basis for a stationary phase. Nosterenko et al. has performed separations of proteins using oxidized/cleaned diamond and Saini et al. has been successful in coating the diamond surface with poly(allylamine). This coated diamond was then used as a normal phase in Solid-phase Extraction (SPE). Saini's study also showed that his phase was extremely stable under extreme pH conditions (from pH 0-pH 14) for 24 h. The SPE column was able to be reused many times and showed no signs of degradation. It also performed in the same manner experiment after experiment and only required a flush with ethyl acetate in between uses.
These two groups have shown that separations can indeed be performed with diamond as the basis for a stationary phase. Nesterenko's study lacked good resolution in it HPLC spectra and Saini's capacity was quite low, but efforts are being made to remedy the capacity issue.